Q9 ~ How does Protagoras’ claim that man is the measure of all things, of the things that are, that they are, of the things that are not that they are not, serve to link the sophistic tradition with the pre-Socratic naturalist tradition?

9.     How does Protagoras’ claim that man is the measure of all things, of the things that are, that they are, of the things that are not that they are not, serve to link the sophistic tradition with the pre-Socratic naturalist tradition? 

RW: I have kept Karl’s outline from last year (his updates of the previous year’s answer are bracketed), but updated the thesis (the language seemed awkward to me).  I have also included a transitional map sentence (for the intro paragraph of the answer) to go from thesis to content.  I close with a note of how the answer might be expanded, though I’m not sure about it.  I’d love comments.

Thesis – Protagoras continues the Pre-Socratic naturalist tradition by offering an answer to the question: ‘What is the unifying principle of reality?’  Protagoras gives his answer–that man is the unifying principle of reality–on the basis of and in response to the views of the Pre-Socratic naturalists.

RW Transition (map): In this essay I will provide a brief overview of the Pre-Socratic naturalist tradition, then show how Protagoras adapts that tradition to sophistic philosophy, and close by highlighting some similarities and differences between the two traditions.

I)     Pre-Socratic naturalist tradition

A)   The Pre-Socratic naturalists searched for an answer to the question – What is the unifying principle of reality?

1)    For Thales, it was water

2)    For Anaximander, it was apeiron (“the indefinite”)

3)    For Anaximenes, it was αερ (dense mist)

4)    For Heraclitus, it was unity in diversity

5)    For Parmenides, it was unchanging [necessary] being

B)    For the Pre-Socratic naturalists, this underlying reality does not necessarily accord with man’s perception. So the general findings of the Pre-Socratics lead to a distrust of senses.

1)    Heraclitus – everything in flux, you do not step in the same river twice, there is nothing that remains in change (compositional identity thesis).

2)    Parmenides – it looks like there is change, but there really isn’t.

[Both Heraclitus and Parmenides think that there’s a logos (reasoning, account) that governs things.  For Heraclitus, it may regulate the flux.  For Parmenides, it may either be enabled by being, or constitutive of being.] 

C)    Also, the systems of philosophy proposed by the naturalistic Pre-Socratic philosophers excluded one another. The result of this was a mistrust of cosmologies.

II)    Protagoras

A)   Protagoras was a Sophist. With Sophism there was a change in the subject and method of the philosophy of Pre- Socratic naturalists.

1)    The Sophist’s subject

(a)   There was a turn from the cosmos (macrocosm) to man (microcosm).

2)    The Sophist’s method      

(a)   The previous method was deductive – when a philosopher had settled on a general principle of the world, he explained the particular experiential phenomena in accordance with his fundamental principle.

(b)   The Sophists, in contrast, used induction. For example, they might draw from variety of opinions and beliefs to argue that nothing can be known with certainty.

B)    Protagoras’ solution was to argue that the unifying principle of reality is man.

1)    "A human being is the measure of all things -- of things that are, that they are, and of things that are not, that they are not.”

III) Similarities & Differences

A)   Protagoras, like the Pre-Socratic naturalist philosophers, wanted to have an account of reality by appealing to one fundamental aspect of reality.

B)    For the naturalist philosophers, it was something natural. For Protagoras, it was man. [The Heraclitean Logos, common to all, is an intermediate step, since it’s not (obviously) merely natural, but is still common to all humans.]

C)    The cosmologists wanted objective truth, whereas for Protagoras and the other sophists their end was practical.

[Karl: A fruitful way to answer this question might be to compare Protagorean man’s activity with Parmenides’s passivity and receptivity e.g. in the Proem.  Ryan: I don’t know what Karl means.  J]

[Ryan: It might also be worth making a II.C., noting the connection Plato draws between Protagoras and Heraclitus in the Theaetetus, where Heraclitus’ metaphysic­­–all is flux–seems to undergird Protagoras’ epistemology–knowledge is perception.  Thoughts?  Is this worth noting?  If so, is there a better place to put it?]